Interest in renal gene transfer has increased in recent years through the accumulating information acquired from the sequencing of the human genome. A wide variety of genes have been cloned for inherited genetic disorders and genes involved in the progression of renal failure. One of the main problems in developing gene transfer techniques to the kidney is largely due to the complexity of the renal anatomy, which has numerous distinct structures (i.e., vascular, tubular or interstitial) within different regions of the kidney. The present proposal is designed to determine whether a recently developed self inactivating lentiviral vector system based on human immunodeficiency virus can be utilized as an efficient gene delivery method to the kidney. The studies in this proposal will investigate several issues: first, the effect of changing promoters and cis-acting DNA elements into the integrating vector; second, determining the efficiency of transduction using different routes of lentiviral vector administration; and third, the role that the cell cycle plays in the efficiency of transduction into different regions of the kidney in vivo. Initial experiments will be to clone different promoters and/or cis-acting DNA elements into the lentiviral vectors to maximize gene expression in the kidney in vivo. In addition, the optimal route of administration needs to be elucidated, and so we propose to inject lentiviral vectors through different routes: the renal artery, the ureter or directly into the renal interstitium. The different infusion methods will allow us to determine which cell types will be transduced depending on the direction of the infusion (i.e., anterograde into the renal artery or retrograde into the ureter). Another important biological question that will be addressed is whether cell cycle progression, such as hypertrophy and hyperplasia, will enhance the transduction of lentiviral vectors into renal cells in vivo. Experiments will be designed to compare whether cells undergoing hypertrophy transduce as effectively as cells that will be either quiescent or undergoing hyperplasia. In all, the studies proposed in this grant should allow us to better elucidate the biological and virological factors necessary for efficient entry and integration into renal cells by lentiviral vectors in vitro and in vivo.